This application claims the priority of German application 196 17 562.3-16 filed in Germany on May 2, 1996, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a vehicle air-conditioning system in which air blown by one or several air outflow nozzles into the vehicle interior can be changed as a function of the sun radiation. For this purpose, an automatically adjustable air guiding arrangement on the air outlet nozzles are appropriately controlled by an air-conditioning control unit.
A vehicle air-conditioning system of this, type is described in U.S. Pat. No. 4,434,932. In that system, the air guiding arrangement can be controlled by a control signal of the air-conditioning control unit. When the signal level increases, the air guiding arrangement aims the outflowing air current more at the area of an associated vehicle seat, and when the signal level decreases, it directs the outflowing air more and more away from the area of this seat, or keeps it away from it altogether. The control signal is generated as a function of the output signals of a sun radiation sensing system and an outside temperature sensing system, as well as a determined difference between a predeterminable desired value and an actual value for the interior vehicle temperature (measured by an inside temperature sensing system). The signal level is increased by a certain value to achieve a stronger air-conditioning cooling effect when the measured sun radiation intensity exceeds a given threshold value. In this case, the sun radiation sensing system can be designed to sense separately the sun radiation on the left and right vehicle sides, so that the left and right vehicle seat areas can be air-conditioned separately, dependent upon the sun radiation impinging thereon. In addition, by using a seat occupation sensing system, the air guiding arrangements can be automatically adjusted only for those vehicle seats which are occupied.
The object of the invention is to provide a vehicle air-conditioning system of the above-mentioned type which achieves a comparatively comfortable air conditioning for the individual areas of a respective vehicle by targeted adjustment of the respective air guiding arrangements.
This object is achieved by a vehicle air-conditioning system according to the invention, which is designed such that it can sense not only the intensity but also the direction of the incident sun radiation. By means of this information, and vehicle-specific geometrical data (particularly with respect to the position of the vehicle seats in the vehicle interior and the position of the vehicle window surfaces), the air-conditioning control unit can determine the local sun radiation for each respective vehicle seat, in a locally resolved manner, for each region of the whole area of a vehicle seat, and thus for each body area of an occupant of the seat. The air-conditioning control unit generates control commands for automatic adjustment of the air guiding devices assigned to each seat as a function of this radiation information, so that air can be aimed in a targeted manner at those seat regions (and therefore at those body regions of an occupant of the seat) which are subjected to the greatest sun radiation.
In one embodiment of the invention, a seat position sensing system is provided (as is customary; for example, for automatic seat adjusting systems with a so-called memory function for the user-individually preselected automatic seat adjustment). By means of this seat position sensing system, the air-conditioning control unit can comparatively precisely determine the spatial position of the different areas of the vehicle seat, and thus the spatial position of the individual body regions of an occupant of the seat.
In another embodiment of the invention, cooled air is aimed at those seat regions (and thus at those body regions of a seat occupant) which are subjected to direct sun radiation.
Still another embodiment of the invention includes an air intake blower whose operation can be adjusted as a function of the sun radiation, so that cooled air is blown into the respective seat regions in a direction which depends on both the direction and intensity of the sun radiation.
According to another embodiment of the invention, -at low outside temperatures, warm air can be guided with priority into the seat regions adjacent to the cold vehicle windows, so as to prevent an excessive cooling of the corresponding body regions of a seat occupant.
In still a further embodiment of the invention, when the difference between the actual and the desired interior temperature exceeds a certain amount, so that cold air is supplied with priority into the central upper seat region (and thus at the upper body or head of a seat occupant), the system blows warm air for additionally heating the foot space.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.